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Is C50 a superaromat? Evidence from electronic structure and ring current calculations
Ana Sanz Matías1, Remco W A Havenith2, Manuel Alcamí3
1Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium. ana.sanzmatias@chem.kuleuven.be arnout.ceulemans@chem.kuleuven.be.
Physical Chemistry Chemical Physics : PCCP
|October 8, 2015
Summary
Fullerene-50 cages exhibit varying degrees of spherical aromaticity. Magnetic properties are sensitive indicators of this, with D3 isomers showing superaromaticity and D5h isomers displaying deviations and countercurrents.
Area of Science:
- Computational Chemistry
- Materials Science
- Quantum Chemistry
Background:
- Fullerenes are carbon allotropes with unique cage structures.
- The 2(N + 1)(2) rule identifies 'magic number' cages like fullerene-50.
- Understanding fullerene electronic structure and magnetic properties is crucial.
Purpose of the Study:
- To investigate the sphericity and aromaticity of fullerene-50 isomers.
- To analyze the electronic structure and magnetic response of C50 cages.
- To correlate fullerene stability, aromaticity, and magnetic properties.
Main Methods:
- Calculation of sphericity index for C50 isomers.
- Analysis of π-orbital spherical parentage.
- Computation of current density in an applied magnetic field.
Main Results:
- The D3 isomer of C50 shows high spherical aromaticity (superaromat).
- D5h isomers exhibit electronic structure deviations and reversed spherical parentages.
- Fullerene stability does not correlate with aromaticity, but magnetic properties do.
- D3 cages display global diatropic currents, while D5h cages show local paratropic countercurrents.
Conclusions:
- Magnetic properties are sensitive indicators of spherical aromaticity in fullerenes.
- Sphericity breakdown in C50 cages leads to distinct magnetic current patterns.
- The D3 isomer represents a highly spherical, superaromatic fullerene cage.
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